Replacing Bmw E90 Auto Transmission Oil Pan: Step-By-Step Guide

To replace the automatic transmission oil pan on a BMW E90, you will need a fluid pump, a 17mm wrench, and automatic transmission fluid. You will also need a filter and gasket kit.

The process involves draining the old fluid, removing the old oil pan, and replacing it with a new one. This can be done by following these steps:

1. Jack up all four corners of the vehicle and place it on jack stands.

2. Place a drain pan under the transmission and remove the fluid drain plug. Allow the fluid to drain completely.

3. Remove the transmission pan mounting fasteners and clean any dirt and debris from around the transmission pan.

4. Remove the old gasket and discard it.

5. Install the new transmission pan and tighten the fasteners.

6. Fill the transmission with the correct amount of fluid.

7. Start the engine and apply the parking brake.

8. Shift the transmission through all gears to circulate the fluid.

9. Monitor the transmission fluid temperature and add more fluid as needed.

Tools and parts required

The tools and parts required to replace the transmission oil pan on a BMW E90 will vary depending on the specific model and year of your car. However, here is a general list of what you will need:

• Jack stands or car ramp
• Transmission jack (optional but recommended)
• Milk jugs or other measuring container
• Clean shop rags
• Fluid transfer pump
• New transmission oil pan
• New transmission oil filter
• New transmission oil pan gasket
• New transmission fluid (refer to your owner's manual for the correct type and amount)
• Gasket scraper or gasket removal tool
• Torque wrench
• Allen wrench set
• Socket set
• Safety goggles

Note: Some of these tools may be optional or already included in a standard tool kit. Always refer to the specific repair instructions for your vehicle and consult a qualified mechanic if you are unsure about any aspect of the job.

Jacking up the car

Tools and Materials Required:

• Floor jack
• Jack stands
• Wheel chocks
• Jack pad

Step-by-Step Guide:

• Park the car on a level, solid ground: It is important to choose a flat and sturdy surface to park your car. This will ensure stability and safety while you work.
• Block the wheels: Use wheel chocks to block the wheels that are not being jacked. This is a crucial safety measure to prevent the car from rolling.
• Place the jack: Refer to your car's manual or the jack manufacturer's instructions to identify the correct jack points. Place the jack at the designated jacking points, which are usually located just behind the front tires and in front of the rear tires.
• Lift the car: Use the jack to slowly lift the car to the required height. Make sure to monitor the jack and vehicle position during the lifting process.
• Secure the car with jack stands: Once you have achieved the desired height, place jack stands under the jacking points to support the vehicle. Slowly lower the car onto the jack stands until its full weight is supported. Ensure that the jack stands are stable and not tilting or moving.
• Additional support: For added safety, you can place an additional jack stand or support under the vehicle.

Note: Always work on a level, solid ground, and use tools that you trust. Remember to block the wheels and never rush the job.

Removing the transmission under-cover

To remove the transmission under-cover, follow these steps:

• Jack up the front of your car first and place jack stands at the jacking points on the sides of the car.
• Jack up the rear of the car under the differential and place jack stands.
• Using an 8mm socket, remove the transmission under-cover.

Removing the fill and drain plugs

To remove the fill and drain plugs, you will need to jack up your car. Place jack stands at the jacking points on the sides of the car. You will need to jack up the front of the car first, as it is rear-wheel drive. Then, jack up the rear of the car under the differential.

Next, use an 8mm socket to remove the transmission under-cover. Then, use an 8mm Allen wrench and a 17mm wrench to open up the fill hole. Place an oil-catch under the fill hole, as a lot of oil will spill out.

Now, use a 10mm Allen socket to open up the drain plug. Place the used oil in a container to see how many quarts came out of your transmission.

After that, fill the transmission with new oil until it starts to overflow. Re-install the fill plug and start the car. Shift through the gears slowly while pressing down on the brake.

Finally, with the car still running, place your hand on the transmission pan to check the temperature. When the car is warm, open up the fill hole and check if oil is coming out. If not, fill the transmission until it does. Re-install the fill plug, re-install the trans cover, and jack the car down.

Cleaning the mating surfaces

To clean the mating surfaces effectively, follow these steps:

• Use a plastic or composite scraper to remove any large pieces of dirt, debris, or old gasket material. Be careful not to use a metal tool as it can damage the soft aluminum surface.
• Apply a suitable cleaner, such as brake cleaner, acetone, or lacquer thinner, to a clean rag and wipe down the mating surfaces. This will help remove any residual oil or grime.
• Alternatively, you can use a wire brush or metal-brush sandpaper to scrub the mating surfaces and remove any stubborn residue. Ensure that you do not get any debris inside the engine.
• Once the mating surfaces are clean, make sure they are completely dry before proceeding to the next step.

It is important to take your time during this process and ensure that the mating surfaces are thoroughly cleaned. This will help prevent future leaks and ensure a proper seal for your new transmission oil pan.

Frequently asked questions